A light emitting diode (LED) is one of light emitting devices that emit light when a current is supplied thereto. LEDs can emit light having high efficiency at a low voltage and thus have a high energy saving effect. Recently, a problem with the luminance of LEDs has been significantly addressed, and LEDs are being applied in various devices such as backlight units of liquid crystal display (LCD) devices, electronic sign boards, indicators, home appliances, and the like.
LEDs may have a structure in which a first electrode and a second electrode are disposed on one side of a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer. However, when a light emitting device, which has a lateral structure in which first and second electrodes of a light emitting diode are respectively connected to first and second lead frames through wires, is used as a light source of a backlight unit, it is difficult to miniaturize the backlight unit due to the wires and the light emitting device is also vulnerable to heat dissipation.
Nitride semiconductors are attracting great interest in the development fields of optical devices and high output electronic devices due to their high thermal stability and wide bandgap energy. Particularly, blue light emitting devices, green light emitting devices, and ultraviolet (UV) light emitting devices using nitride semiconductors are being commercialized and widely used.
In the conventional general reflow method, when a flip chip package is manufactured, an ablative material called a flux is applied to a solder and is melted by applying heat. This method has a problem in that the solder is disconnected because of the risk of remelting when the solder is bonded.